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Category: Vanagon Waterboxer Engine

There is no substitute for experience so I thought that I would share a few of those experiences which can bring you up short. In other words,some lessons are well learned. I have made most of the mistakes one can make under the valve cover and I have reviewed the remains of other people’s mistakes for instance, rubber mounted rockers when the wrong rocker gaskets are used by mistake. Do you have any oil leaks?

What is so complex about the stuff under valve cover? Looking at it you see a metal cover, the clips (bails) that hold it on, some bolts the gasket the rocker arms and the often fooled-with adjusters.

I have made some expensive mistakes with the valve covers that I have installed. One such example comes from my racing days. One day at the track just before the race,and after adjusting the valves I reinstalled the valve covers on a Formula Vee engine. I had done that many times before. No big deal, right. I found out the hard way that the valve cover was leaking it. The car was smoking to beat the band in the hard right turns. I had not checked the covers for leaks. I lost the race, the crankshaft, and the connecting rods. However I gained experience which has lasted 20 plus years; check your valve cover for leaks every time you reinstall them. That means let it run and look to see that it is dry. It may take a few minutes for the oil to get up to the cylinder head. This effort is well worth the wait. When installing the valve cover always I put a fresh gasket on! I do not glue them on so I can’t get them off later. If it still leaks try a new bail . They are less that two dollars at the dealer and they hold the cover tight against the head. You may find that the valve cover is just too old, rusty or bent. Try a new one.

So your heater box is wet with oil and your’e sure the cover isn’t leaking. Push rod tube gaskets and lower head studs can be responsible. There are expandable push rod tubes to repair any leaks that come from the tubes or tube seals. When rebuilding air cooled engines I seal the studs inside the valve cover with silicone (non- corrosive kind). This could also be done at any time if the parts are free of oil. By the way, on some of the early 36 hp and 25 hp engines the lower cylinder head nuts had an o-ring which seals the lower stud holes.

Adjusting those valves must the simple part right? So you just adjusted your valves but they sound like the Hammers of Hell’. What gives? The answer may be the head temperature. The valve lash increases with temperature on all but the oldest stale air engines with long rocker studs. Anytime the oil temp goes over 200F degrees the cylinder heads can over-heat and that can show up as a noisy valve train.

Perhaps the engine is not too hot but one or two valves are ticking away. You’ve gone back and tried adjusting them again and you are sure that the valves are set correct but the ticking noises remain! What to do? One possible answer is that the valve is not adjusted to the clearance of the feeler gauge you’ve used. The gauge simply bridged the dish in the end of the valve stem.

Since the tip of the valve stem wears over time, it’s possible the feeler gauge can not flex enough to accurately reflect the lash the rocker will have and thus the ticking noise. Try adjusting it by feel with no feeler gauge. The rocker needs to move about the thickness of a dollar bill (.004ths).

Lash caps are one way to deal with valve stem wear These go over the stem and give you a flat surface. The rocker stands may need to be shimmed to make room for adjustments. I shim the rockers on every engine I build to set the geometry. Every manual covers geometry but its rarely paid atten valve guide.

Also repeated loss of valve clearance on the exhaust valve indicates stretching valve stems or valve seat erosion. It is then time to remove the heads for inspection and a proper valve job.

I hope sharing my experiece’s under the valve cover helps you avoid some of the problems I’ve incountered. As a famous guy once said “Those who don’t know history are doomed to repeat it”.

I have had more than one 2.1 water boxer engine brought in for rebuilding with symptoms of low oil pressure. Despite having put in the longest spring the customer could find for the pressure relief and adding thicker oil, the engine still had low oil pressure at a warm idle. These findings had been confirmed with a gauge. So as I disassembled these engines I was very careful to check for excessive clearances. It turns out the clearance between the rod bearing and the crankshaft rod journal had gotten to the point that it allowed the oil light to come on at warm idle. Unfortunately the more common results of this problem in the 2.1 is that the rod winds up hanging out of a new vent hole its has created in the top of the crankcase. The 1.9 on the other hand is not known for throwing rods unless it was run low of coolant or oil.

The one thing that has been consistent in all the 2.1 engines I have stripped and measured is that the large end of the connecting rods are no longer round. With this problem in mind I started paying more attention to the big ends of all the water boxer con rods that came into the shop. The first thing I found was that the 1.9 and the 2.1 con rods are the same size and length. In fact they are the same rods. My inspections showed the 2.1 rods had consistently more distortion at the big end. What is the difference between the two applications of the same con rod? The stroke is longer in the 2.1 engine so the rod angle is greater, plus the 2.1 make more power witch puts more strain on the rods. Itâs clear to me from my days at the race track that nothing distorts con rods faster than exceeding the power curve but the fuel injection has a nifty rev limiter built right in. This doesnât explain why we see rod distortion in one engine and not the other. Next I went to the Bentley book to compare the torque specs. The 1.9 rod has a reusable rod bolt that call for a torque of 33-ft. lb. and the 2.1 has torque of 22-ft. lb. plus ¸ turn. The manual also says not to reuse bolts on the 2.1 engines.

The conclusions:
1) Never reuse the rods without having the big ends rebuilt ever!
2) Never rely on Plastagauge alone it does not always show if it’s out of round
or if the cap is shifted.
3) Consider rebuilding the engine when the heads start to leak if it has got a hundred thousand
or more miles on it. Keep in mind the core may not be rebuildable if you wait longer. There is
no doubt the rods are the major reason for the catastrophic engine failures.

More than one person that has told me that they only got six thousand mile from a rebuilt 2.1 long block before a rod blew through the case. They also told me the big ends of the rods had not been measured or rebuilt. The facts speak for themselves. I see this problem on a daily basis and thought I should pass on my observations.

Just as with the engine in a brand new car, a rebuilt engine needs a break-in period to insure long life and low oil consumption. The new rings, lifters and valves have to find their place in the scheme of things.
The new rings and cylinders generate a lot of friction during the break-in. The bore has a cross-hatch scratched into it, and dragging rings across the freshly honed bore creates initial frictions that are only there until the rings seat. Three rings on four pistons moving up and down real fast, even at low RPM, create a lot of heat in a new motor, and this is extra heat the new motor has to contend with.

Oil is a very good heat exchanger as well as lubricant. I change the motor oil twice in the first thousand miles. Any name-brand 10-30 oil will do the job. The used oil comes out looking like metal flake because it has the residue from the rings and cylinder walls.

You will see a decrease in crankcase pressure when the rings finally seat properly.

I use new or reground OEM (Original Equipment Manufacturer) camshafts and German lifters in my engines. If lubricated properly, these pieces will work-harden. If they become dry, they will scuff and wear out rather than break in. After-market camshafts are not induction-hardened as are the OEM camshafts, and must rely on a hard lifter to harden themselves. I prefer a hardened camshaft to start with. This makes an even playing field for all the parts.

A fresh valve job produces a good seal in the heads and good compression. (Pressure is heat!) Valves will work into the seats very quickly and the clearance needs to be checked twice in the first thousand miles. I am also very big on spring tension. Those valves should follow the camshaft as closely as possible. They should not float. Most valve-train damage occurs from pounding as they float. I use new springs and sometimes shim them for higher pressure.
The rebuilt engine is oil- and air-cooled, and, as you can tell, overheats even before putting a load on it. So how can you take care of this overheating new engine you just spent money on?

Keep it as cool as possible. Make sure you install the whole cooling system and all fresh-air tubing. Set the timing as best you can. Before you actually start the engine MAKE SURE you have oil pressure. Crank it over with the coil wire removed and watch for the oil light to go out. Now attach the coil wire and start the engine.

Above all, let it idle for at least the first twenty minutes. Keep it at 1500 RPM for that time. The reason for this is to keep the cooling fan spinning fast enough to properly cool the oil and heads. Driving it for that first twenty minutes (putting a load on it) would be the worst thing you could do. It creates too much heat and the fan might not spin fast enough. Also, wind resistance on the highway increases with speed and adds to the load put on the engine. This is really true for flat-nosed buses. For this reason, once you do begin driving, keep your speed under 55 mph for the at least the first thousand miles.

One last note about gasoline. If it has been in the car for one year or more, get rid of it. As it enters the exhaust system it is still burning. I have seen exhaust systems glow red-hot because of old fuels.

It has been my experience that small details make or break a project, and these small adjustments and fine tunings are not guess work. After rebuilding an engine, my policy is to review the customer’s installation so that the customer will have the best running engine for the longest possible time. This follow-up is very important, and service not usually offered by other engine rebuilders.

So you’re thinking its time to replace the heads on your water boxer, and you’re asking yourself if you can do a job like this. Can this be done on the ground without a lift? I will try to help you answer these questions. First, lets go over the most common reasons to remove the cylinder heads. Make sure to be clear about what’s leaking before you begin the job. It can be oil or coolant that’s dripping from the heads. Washing the engine is very helpful when looking for leaks. If the push rod tubes are leaking or if a lifter has collapsed, you can use an expanding push rod tube, which is available at the dealer for $50 each, or in the aftermarket for about half of that. The most common coolant leak is from a cracking or splitting rubber outer coolant gasket at the head.

Often this will be accompanied by a corrosive reaction where the rubber gasket contacts the head. Unfortunately, there is no easy way out of this repair. The heads must be removed to replace these gaskets, and at this time a close inspection of the heads will indicate the extent of corrosion. A corroded head will not make the best possible seal with the gasket.

Another reason the heads may need to be removed is pressure build up in the cooling system. This is do to the head gasket at the top of the cylinder leaking compression when the engine is cold.

TEST #1: Pressure Tests for the Cooling System The first test of the cooling system is done when the engine is cold. A cooling system pressure tester can be installed in place of the radiator cap. Pressure in the cooling system and hot coolant are not something to be treated lightly. Use caution, and never remove the radiator cap from a engine that has been run even for even a short time. After installing the gauge, pump it up to 10 pounds. Look around for leaks if the gauge shows any pressure loss.

Common trouble spots include heads, hoses, water pump and rear heater core. If you smell something sweet when you turn the heater fans on, it may be a coolant leak at one of the heater cores, or simply the O-ring at the rear heater valve leaking. Because there is often more then one leak in the system, it is necessary to continue pressure testing until the system holds pressure.

TEST #2
Start the engine cold with no pressure indicated on the gauge. The pressure in the cooling system builds to aprox 7 lbs at normal running temps looking around for leaks. But if the pressure builds quickly to around 15 lbs the pressure is coming from one of the cylinders through the inner head gasket. This can also show up as a coolant pressure loss in the first test. In extreme cases the cylinder can fill with coolant, and will not turn over. This is know as hydraulic lock, and if you suspect this pull the spark plugs and try to turn the engine again. Pulling the plugs from the engine allows water to escape from the spark plug holes.

DO’S & DON’TS FOR HEAD REMOVALand some things to consider before you attempt this job

Yes, head removal can be done on the ground with a good set of heavy duty jack stands. Disconnecting the battery is the first step. I consider cars to be a fire hazard, since there is everything you need to make a great fire in short order. I have set more than one car aflame.

This is a messy job, and you can expect to spill coolant on the ground. No mater how you jump and dance, those last few drops will get you.

Remove the coolant expansion tank cap and the 6mm Allen head coolant drain bolts between the push rod tubes on each side. I also pull the bleeder from the radiator because it allows the cooling system to drain more completely. Next drain motor oil remove the filter. With the fluids draining, start undoing the ground wires on the left head. Tie rap them together so none are forgotten . They will need to be cleaned and inspected before reinstalling, using new bolts and anti seize compound. Labeling the wires saves time and guessing later. Next remove the alternator and the belts, and inspect the belts for wear and cracks. Check the water pump pulley shaft for bearing play by grabbing the shaft at 12 and 6, and seeing if it wobbles. Now check for leaks at the vent hole on the underside of the pump. If its leaking, this a great time to replace it, since its much easier with the heads off and the cooling system drained.

Unbolt the intake manifolds complete with the fuel hoses and injectors, and tie them up out of the way.

Removing exhaust bolts and studs at the head to exhaust connection is one of the hardest parts of this job. Use only six point sockets, trying not to round the heads off. When the head of the fastener is rusted you may need go to the next size smaller socket installed with a hammer or nuts can be spilt then turned off the stud. Drilling or sawing the head off the bolt works, leaving the remainder of the bolt to grab and remove after the head is off the engine. The exhaust brackets are very important and need to be reinstalled they keep the exhaust pipes from flexing and cracking as the engine moves.

Inspect the adjusters when removing the rocker arms. They take a beating and can be hard to get on short notice.

Keeping a parts list is key to a smooth, timely and effective repair. Faced with the option of using something that is junk, or waiting for my second parts order to arrive, I’ve had to re-use the tired part. I can’t have my grocery getter off the road for too long.

WORDS TO THE WISE
Cylinders do get stuck to the head and taping (hitting) the head just below the exhaust ports with a plastic compethan mallet helps. Going from side to side helps to separate the head from the cylinder. You may need to push the head back in place and start again if the head moves more than two inches with the cylinder still attached. The piston in the stuck cylinder should not be at the bottom of its stroke. DO NOT pull the head and cylinder off as one because piston rings cannot be compressed to put the cylinder back on until you remove the piston from the engine. Wrist pins and pin clips are hard to access and remove even when using the expanding pin tool and the oxy acetylene torch to soften up the varnish on the pin. The #1 and #3 the pistons are first to be installed and last to be removed. This means the # 2 or 4 cylinders are in the way and must be removed before the 1 or 3 piston pins can be accessed for removal. Then the time comes to install the #2 and #4 piston pins the inaccessibility of the con rod creates a real challenge. Volkswagen has a special tool (#3090) that supports the connecting rod while you install the wrist pin. One possible solution is to modify a coathanger to do this, but I find it faster to remove the engine and reinstall pistons and cylinders on the engine stand, because I can rotate the engine onto its side. The o-ring at the bottom of the cylinder is not likely to leak if you disturbed the cylinder. I Boston bob have never heard it to be a problem but having said this I’m sure I will now here otherwise.

Pistons, cylinders and rings do not show signs of wear like the air cooled engines.The oil consumption is typically not high and the pistons and cylinders do not need to be replaced normally unless over heated or you are doing a total rebuild.

PARTS NEEDED TO REASSEMBLE Options for cylinder heads: OEM @$625 each at the dealer, Spanish AMC after market heads @$450 each. We do not use the valves that come with these heads.

There couldn’t be a better time to replace the water pump or any weak exhaust pipes, injector seals and high pressure injection hoses. I recommend using only OEM sealant when resealing cylinder heads. Some silicones can be corrosive when used on aluminum.

Most coolants are now suited for aluminum engines, so read the label on the coolant you are thinking of using. Corrosive inhibitors can be purchased to supplement the coolant, but I don’t think it is necessary if the antifreeze is changed every two years.

How do I know if it is time to replace the lifters? The lifters are hydraulic, and tired lifters take longer to pump up, if they do at all. Lifter replacement is judged by how long you hear the ticking when the engine is cold. There is no extra labor involved to replace the lifters when the heads are off.

I have tried the procedure in the Bentley book for filling the lifters with oil, and they still take time to quite down when they’re new. I recommend soaking the lifters in oil overnight before installing them. This is just as effective.

PARTS # list

Part

Number

Notes

cylinder head for the 1.9:

# 025 101 355

(2.1 heads will work)

cylinder head for the 2.1:

# 025 101 355C

(1.9 heads will work)

gasket set (one per side):

# 025 198 012B

black sealant for black coolant rubber gasket:

# D-000-40-01

yellow sealant for head nuts:

# AKD 456-000-02

valve cover (all years):

# 113 101 475 B

cover clip (all years):

# 043 101 487

cylinder head nuts (all years):

# N 901 841 01

push rod tubes 8 needed (all years):

# 025 109 335

water pump 1.9:

# 025 121 010A

water pump 2.1:

# 025 121 010C

thermostat (all years):

# 025 121 113 F

thermostat o-ring (all years):

# 034 121 119

2.1 heat exchanger water hoses at oil filter:

# 025 121 058D &
# 025 121 058G

(These are considered mandatory replacement at this time. They supply coolant to the heat exchanger that is between the oil cooler and the block

short coolant hose from water pump to head:

# N 901 287 03

Mandatory (Same # for the cross over pipe union under pulley if needed.)

expandable push rod tube

: # 025 109 337

(If you have a leaking tube or a junk lifter this makes it possible to repair without removing the head. Priced at $50 each at the dealer, also now in the aftermarket for half of that).

hydraulic lifers:

# 022 109 309

valve adjusting screws 9mm:

# 025 109 451

rear heater core (all years):

# 321 819 109

o-ring for rear heater valve:

# 861 819 297

exhaust gasket:

# N 901 316 01

(For collector to exhaust pipe connection. This isn’t included in the head gasket kits, and two are needed.)

Run the tap into the head nuts, making sure they are clean inside. Next, take the 10×1.50mm die and clean the head studs.

The lip that holds the head gasket on the block needs to be inspected for burs and rot. If needed, wire brush and clean. I use Jb weld epoxy in the eroded surface to restore its shape, filing it in aprox. 24 hours when dry.

Install the inner head gaskets in the head with a dab or to of grease to hold it in place. Next do the rubber gasket on the block. Apply the black sealant to the black water gasket in the middle of the gasket. Put the head onto the studs, leaving room to install the push rod tubes. I use the push rods to hold up the push rod tubes until they are all in place. Next start one of the center head nut inside the valve cover to tension the tubes, then inspect the tube gaskets toassure proper alignment. Turn the one head nut you started so you can start the other nuts. I apply the yellow head nut sealant to the opening in the head for the stud and to the nut itself, trying to it keep it from getting in the nut. Using the torque pattern in the book bring the head down evenly. This can take two or three times to get the nuts ready for final torquing. The torque for the heads is 20 ft lbs, then 36 ft lbs with a bar type torque wrench.

PUSH RODS
The push rods can hang up on the edge of the lifters which results in no compression. There are some simple tricks to installing push rods. First I have heard that greasing the push rod tip when installing the push rod can help. When I install push rods I push them in, then lift the far end and push again. This is done with the rocker arm installed, using light pressure to hold the rocker in place until you feel the push rods are seated, then install the nuts. A good pen light is very useful to see the down in the push rod.

BLEEDING THE COOLING SYSTEM
I’ve heard more ways to bleed the cooling system than you can imagine. Some may even work. Here’s what I do. Its simple and it works. This is done only then the engine is cold. Coolant, when heated up to running temps, will give you a good burn. I lift the nose of the van about 4 inchs. Fill the cooling system with coolant. Let stand ten or fifteen minutes with heater valves open. Top off again, and let stand for another five minutes. For the best results, remember to pre-mix fresh coolant with equal amounts water. Next, start the van with at least a full jug of pre mixed coolant at your side. Rev the engine to 1,500 rpm and expect to pour coolant in the expansion tank. Don’t let it get low. When the coolant is coming out of the radiator in a steady stream, plug the bleeder in and tighten it. Top of the coolant, tighten the cap, let off the gas, and you’re done. This has worked for me repeatedly.

THE LAST DETAILS
Checking the timing and exhaust emissions are the finishing touches to any engine work. Exhaust gas testing lets me see just how well the engine is burning the fuel. The test must be done before the catalytic converter. That is what the plug in the exhaust collector pipe is for. Testing after the cat just shows if the cat is working and it fails to show how well the engine is burning the fuel. This is also the time to check throttle switch operation. If its clicking its probably working.

Checking the radiator fan and switch is important if the fan does not cycle or responds later (hotter) than you would like. It is most likely the thermal switch that is screwed into the radiator. These do fail, and will also in time be less responsive to temp increases.

The thermostat restricts the coolant flow to the radiator until the engine achieves proper running temps. There are thermostats that have lower temps and fit the housing.

Another good thing to test or just replace at this time is the coolant temp sensor (also called ntc sensor) for the fuel injection control unit. This test is covered in the Bentley book.

TOOLS NEEDED FOR HEAD REPLACEMENT

• 6mm Allen wrench 3/8 drive• torque wrench bar type recommended• metric socket set• metric wrench set• 2 ton floor jack• heavy duty jack stands I like the 5 ton stands• drain pan or two for oil and coolant• pick for o-rings at top of jugs• something to clean the head surface with wire brush or a sharp scrapper• 10×1.5 mm tap and die to clean the head nuts and studs• hammer and a good chisel for stubborn nuts• screwdrivers misc• plastic compethan mallet for head removal

Final Notes My contacts at vw tell me this head gasket and corrosion problem is unheard of in Europe. They suggested that fuel might be the problem, but I don’t know how fuel could contaminate the coolant. The difference is that the fuel system the vans in Europe are carburetored, not fuel injected as in the states. This could this play a roll. VW now prorates this repair by mileage. Call your local VW dealer for the latest information.

There are performance problems that have been traced to the hydraulic lifters that are in some air-cooled and all water boxer VW engines. Among the symptoms are noisy lifters on cold start. However keep in mind that if the van has been parked for a few days one or more lifters can bleed down and this can be the reason for the noise and does not necessarily mean that there are lifter problems. The symptoms of the lifter problems I am talking about in this article are low idle when cold, hard or not starting hot, poor performance when the engine warms up and the power (vacuum) assist brakes may not work as well at times because of the low intake manifold vacuum. These symptoms can be caused by improper hydraulic valve setup. This article is about how to properly setup the vanagon engine with hydraulic lifters. There have been a lot of differing opinions and methods regarding proper setup of hydraulic lifters.

This issue of proper setup has haunted me for years and cost me lots of time, money and peace of mind. In fact one of my own vans would not start hot unless it was push started or it was left to cool off for a couple of hours. This went on for 2 years with no trace of a reason until I understood that it was the lifters.

It’s no understatement when I say I have lots of trouble and limited success with preloading of the hydraulic lifters in the VW busses and Vanagons. In fact I have had lifters that would not take any preloading at all. It has been suggested that because the lifters are installed on their side that they trap air above the check ball that’s in the center of the lower piston that’s inside the hydraulic lifter and I agree. Air bound hydraulic lifters that are preloaded or that are set to O lash (no clearance or preload) do not allow the valves to close completely after the engine warms up. I believe this is due to the air in the lifter expanding as the engine warms up. I now understand that installing new or used lifters pre-loaded (no valve clearance) may NEVER allow the hydraulic lifters to displace the air remaining in the lifter because the plunger’s travel in the lifter body is minimized.

A long time ago I gave up trying to fill the lifters per Bentley and never looked at those pages again until I spoke with Stan at Bentley publishing who pointed out that there are two versions of the lifter bleeding process in the book (on page #15.7 and 15.24). I personally found both descriptions confusing. The first method instructs you to fill the lifter with oil and then install the lower piston using a scribe to bleed off the oil under the piston as you press the piston into place. As for installing the lifter socket into the lifter they don’t tell you that after you get the lower piston in place it travels back up when you let it go of it, leaving no room to install the lifter socket and clip. The second procedure would have you compress the lifter in a press with an old push rod and purge the air as the lifter is submerged in oil. They don’t say the procedure can take as long as ten minutes per lifter and that a hydraulic press is needed. So I, as most people do, put only enough oil in the lifter so I can compress it enough to get the clip installed.

In the Past

When trying to adjust the valves on a rebuilt engine, or when working on an engine that has had the heads or rockers off for a few days or when replacing lifters I have recommended the following. Set the valve lash to .006″ (i.e. no pre-load). This does two things: first the valves will for sure close all the way when the engine warms up, and, secondly, the piston in the lifter is now traveling it’s full range of movement has a much better chance of pumping out any remaining air. Run the engine for a couple of weeks before trying to preload the valves. Bring the engine up to running temp then let it cool down to the point that you will not burn yourself when you start to work on the engine. While the engine is still warm restart it for no more than 30 seconds and check for any valve noise. If you hear noise, drive the car for a few more days and check it again. Next, remove the valve covers, bring each piston to TDC, and turn the adjuster screws in ¼ to ½ turn. If the valve opens when you turn the adjusting screw in this means the lifter is fully pumped up with oil and you can tighten the lock nut. In most cases the lifters will now self-adjust and allow the valve to fully close and stay pumped up. If instead of the valve opening, the rocker arm moves the lifter as you turn the adjuster, then re-set it to .006ths clearance, reinstall the valve cover, and recheck it in a few days. The idea is to replace any unwanted air in the lifter with oil.

So what’s new?

In the past week I had a customer call and tell me he had not tightened the bolts on his torque plate – the ones that hold the plate to the converter – and after 1400 miles, and having no luck finding that rattling noise, the final bolt came loose, the engine seized, and the van stopped moving. I offered to help him repair the engine. When he dropped it off I got the rest of the story. It seems that after a highway run of less than an hour at 65 mph he pulled in his drive way and let the engine idle and the oil light came on. He also reported that he thought the engine was down on power. At this point I felt that I might learn something if I took the engine apart. So I offered to do so at no expense to the customer and he agreed.

The first thing I did was to put the engine on the engine stand and install a flywheel and put my cut up bell housing and starter motor on so I could spin the engine and test the oil pressure. The oil pressure was at the low end of the normal range 45pds with 10/30. The next test was the compression test and it was 125 on all cylinders a – little low but still ok. Next step was to look at the rockers and check to see if the customer had preloaded the valves. Some valves had lost clearance while others still had approximately .006ths. I was very surprised to see that some lifters were still soft and air bound because the customer had not reported any lifter noise. When the engine was disassembled I inspected and measured everything. The inspection revealed that the only damage or problem was that the customer had scuffed all four pistons on the load side (the load side of the piston is the side that is pressed against the cylinder wall as it’s pushed down on the power stroke).

I was a little disappointed not to have found more of a problem that would explain the oil light coming on (even though the customer had pushed the engine too fast when it was new). The customer had agreed to buy new pistons and cylinders. I thought that was the end of it with no great discoveries until my engine assembler, John Silva, pulled the lifters apart for inspection. John over filled one of the lifters and could not get the lower piston back down into place and instead of pulling the piston out and removing the oil he tried moving the check ball to one side with a scribe and pushed the piston down with a small screw driver. It dropped down enough to allow him to install the upper lifter socket and clip. The next step is what’s missing from the Bentley procedure. John took the same scribe that was used to release the check ball and installed it in the oiling hole on the side of the lifter body. This held the lower piston down so that he could install the upper socket and retaining clip. Once the clip was in place he tested the lifter by pushing the upper socket. The lifter was hard as a rock indicating that there was no air in the lifter. No other methods that I have tried had these results. This looked promising but I remained skeptical. I asked John to finish bleeding the rest of the lifters in the same way and adjust the rockers to the usual .006″ lash. We would test the compression as usual after the engine was completely assembled. The first compression test showed that we had 135 lbs on all cylinders. Next we preloaded the valves ½ turn and immediately repeated the compression test: some of the valves had not closed so we waited ten minutes and repeated the test. The compression was slightly lower: 125 lbs on all cylinders. Because it was lower we then tested each intake and exhaust port with a vacuum tester to see if the valves were closed and found that all the valves were sealed 100 percent. We next removed the valve cover and checked each lifter by prying on the rocker and looking for movement: all the lifters were still hard as a rock. The next morning we checked for soft lifters and found that the # 2 exhaust valve lifter was soft. We spun the engine again for about one minute using the starter motor and then checked the #2 lifter: it had regained most of its rigidity.

My conclusions

Lifters can be pre-bled and preloaded at ¼ to ½ turn at the time the engine is being assembled provided that the above-mentioned procedure is followed. However, assembled engines always have at least one or more lifters on the lobe of the camshaft holding them open. Open valves have their springs compressed thereby increasing pressure on their lifters. The increased pressure will cause the lifters to lose oil over time. This can be days or weeks, depending on how clean the oil and the lifter’s check valves are. These engines may not have enough oil available to the expanding lifters when the engine is first turned over during the start up procedure. If the oil galley is empty, the lifter can take in air instead of oil and becomes air-bound. An air-bound lifter may expand as the engine heats up, and thereby prevent a valve from closing. To prevent this, some shops use a pre-oiler. Oil is pressure-fed into the oil galleys before the engine is first started.

So, caution must be used when preloading valves on any new engines. Air-bound lifters are hard to detect. Exhaust valves that don’t close completely when the engine warms up will not transfer their heat to the valve seat, as it was designed to. Instead, this excess heat travels down the valve stem and scorches the oil lubricating the valve stem and guides, drastically reducing their life. I have seen this specific damage time and time again on air-cooled engines as little as 10 K miles.

I consider pre-loading valves to be optional. You may never have had this lifter problem before, but I assure you the potential is high and expensive. While the intake manifold vacuum is an easy way to know if the intake valves are completely closed, the only way to be 100% sure all the valves are closed when the engine is warmed up is to do a cylinder pressure differential test (sometimes known as a “leak down” test) that is commonly done on race engines and aircraft. This test measures air pressure going into a cylinder, and how much air remains. 2%-4% is ideal.

By Tom Carrington
I should have known it was coming. The signs were there. I just chose to ignore them. What signs? For the past month or so, I have been topping off the coolant reservoir. Not much, just maybe a pint every couple of weeks. I was kinda worried that I might have a head gasket problem (most Wasserboxer owners live with this constant fear) but there were no drips or puddles in the driveway, or strange smells from the exhaust. The temperature gauge always read fine, so I happily fed my engine’s habit. Life was good.

Or so I thought.

Note: Click on thumbnails for expanded images!

Just a week ago, the habit turned ugly. I noticed a slight smell of antifreeze after parking the van, but still no drips or other visible signs of a leak. I was more concerned, but not enough to fully investigate the problem. I should have. A day later, my Van was leaving a distintive coolant trail along the path I drove. Hansel and Gretel would have been proud. That night, I got under the Van to assess the problem. With the engine running, coolant was spewing out of a small hole in engine, just behind one of the pulleys. No ordinary hole, coolant from this one indicates that one of the seals in the water pump had failed. My preferred FLAPS (Olympic Auto Parts, College Park, MD (301) 474-1030) had a brand new German-made pump in stock, complete with new gaskets and an O-ring for $62.00. A quick check at The Bus Depot web site showed they had a similar pump for $50.00. Since I needed it *now*, off to Olympic it was! 20 minutes later, I had a new pump. Follow along as I go through the steps for replacement!

Tools & Supplies Needed:

12mm and 13mm wrenches and sockets

3/8″ drive ratchet, 3″ and 6″ extensions and universal joint

Screwdrivers

Slip-joint pliers

Gasket scraper, putty knife or razor blade

Sturdy jack and jack stands

New water pump (comes with O-ring and gaskets)

2 coolant pipe gaskets

2 gallons antifreeze

RTV silicone sealer

Large bucket or wide dishpan (To collect old coolant)

The worst part about replacing the water pump is it’s location. Down near the heat shield in front of the muffler with not too much room to work. Mentally prepare yourself for some fancy fingerwork. Some of the work you will do from above the engine, some from through the license plate door, and a little bit from below. In the picture to the right, the pump is behind that single-groove pulley with the belt riding on the top of it. The multi-grooved pulley is bolted on the end of the crankshaft.

Step 1 – Disconnect the Battery:
First things first. We will be working near the alternator, so go ahead and disconnect the battery ground strap. The battery is under the front passenger seat. Sure, you could leave it connected, buy why risk it?

Step 2 – Drain the Coolant:
Unless you are determined to replace *all* the coolant on your engine, don’t bother following the Bentley procedures for draining your coolant. What I did was remove the hoses from the thermostat housing by loosening the hose clamps and tugging them off. I had a large bucket underneath, and managed to capture almost all of the coolant. As long as you are there, you might as well disconnect the 2 temperature senders. Once the flow of coolant had subsided, I raised the passenger side of the van with a jack under the frame just forward of the rear tire to get more to coolant to drain out. After the flow slowed to a small trickle, I lowered the Van back down on all fours. The point of all this was to get the coolant level in the engine low enough so that none would spill out when I removed the pump.

Step 3 – Remove the Water Pump Pulley
The new water pump does not come with a pulley, so the one on the old pump needs to be removed. The pulley is held on to the pump with 3 13mm head bolts. The problem with removing the pulley is that there is no good way to hold the pulley still while removing the bolts. If you have an air compressor, no big deal – just use an impact wrench to “zip” the bolts right off. But here’s a trick for the rest of us. First, loosen the pivot and adjustment bolts on the alternator just slightly. Lever against the housing of the alternator to tighten the belt *much* tighter than you would normally do. Re-tighten the bolts on the alternator and place the Van in gear. With the belt that tight, and the transmission in gear, the pump pulley should be held still while removing the bolts. A 13mm combination wrench will work just fine.

Step 4 – Remove the Coolant Pipes
There are 2 steel pipes that carry coolant from one side of the engine to the other. On the passenger side of the Van, both pipes are secured to the water jacket with bolts or nuts/studs, as pictured to the right. Remove both the bolts and nuts. On the driver’s side, the upper pipe slip-fits into the thermostat housing with an O-ring seal and the lower is bolted to the front of the water pump. It is the bolts that secure the lower pipe to the water pump that will try your patience, seen here to the left. You can just get a 12mm wrench on the bolts, but only about 1/8 of a turn can be made at a time. Take a deep breath, prepare to spend some quality time flipping your combination wrench again and again, and remove the lower bolts.

Step 5 – Loosen Hose ClampsAfter completing Step 4, you deserve a break, so here’s an easy one. The thermostat housing is connected to the driver’s side cylinder head by a short hose. Loosen the clamps on the hose. You will be removing the water pump and thermoststat housing as a single unit. Now is also a good time to remove the hose that goes from the expansion tank to the top of the water pump. Use a regular pair of pliers to squeeze and and hold the clamps open while you work the hose off the casting.

Step 6 – Remove Water Pump
The water pump itself is held on to the engine by a single bolt and 2 studs with nuts. Use a 13mm socket with a universal joint and extension to remove these. At this point, there should be nothing holding the pump to the block, as seen on the right. Once the bolt/nuts are gone, the pump and thermostat housing assembly can be pulled straight back towards the rear of the Van. You may have to wiggle the assembly to get the hose connection from the thermostat housing to the water jacket to break free.

Step 7 – Separate Water Pump from Thermostat Housing
The thermostat housing is attached to the water pump by two long, 13mm head bolts. I had to apply a little of heat with a propane torch to get the bolts to turn freely. The heat helps expand the aluminum of the housing, which releases the housing’s grip on the bolt. Once free, I used a wire brush to clean the bolts, and a drill bit to clean out the bores in the housing. At this point, the disassembly phase of the project is over. If you were thinking of installing a new thermostat, now would be the best time.

Step 8 – Clean All Mating Surfaces
Having clean mating surfaces is the key to preventing leaks around gaskets. Nothing worse than putting everything together and seeing a leak! Use a scaper of some sort to remove any traces of old gasket material from the thermostat housing and the mating surfaces for the coolant pipes. The area on the engine where the water pump mounts should also be cleaned to ensure a good seal. On the left, you can see the sealant residue from the water pump. The view to the right shows the same area, after a good cleaning.

Step 9 – Let the Assembly Begin!
Start by installing the thermostat housing onto the water pump. Next, put a *very light* coating of RTV sealer (I like Permatex Ultra Copper) in the o-ring groove on the back of the water pump. Push the o-ring into the groove, and smear a *thin* coating on the face of the o-ring. Do not use more than a paper-thin coating of sealer! If you do, the excess sealer can get into your cooling system and clog things up!! Put the water pump and thermostat housing assembly back on the engine, and tighten the nuts and bolt. The next step was the worse part for me. Using a new gasket, re-install the lower coolant tube. The bolts are tricky to line up and get started, but take your time. Once both of those are tightened down, take a break….you will want one! The upper coolant pipe goes in much easier. Coat the o-ring with a little RTV, and slide it into the thermostat housing. The other end bolts to the cylinder head on the passenger side. Reinstall the water pump pulley and alternator belt. Put the belt on extra tight to help while torquing the pulley bolts, then loosen the belt back to normal (1/2″ deflection). Re-install all the hoses and tighten the clamps. Hook up the wires for both temperature senders. You are almost done!

Step 10 – Adding Coolant & Bleeding Air
Before adding a single drop of coolant, open the engine-mounted bleeder valve located on the “H” shaped housing above the engine, seen here on the right. This will help prevent air from being trapped in the cooling system. Once you have filled the expansion tank, start the engine. Look for leaks at the pump and all of the hose and pipe connections. As the engine is running, the coolant level in the expansion tank will drop. Keep adding coolant until the level does not drop, and you no longer see air bubbles appearing. Close the bleeder valve.The next step is to get any trapped air out of the radiator. Screw the cap on the expansion tank, and turn off the engine. At the front of the Van, remove the grille around the headlights by turning each of the slotted fasteners about 1/2 turn. Jack up the front of the Van a foot or so and restart the engine. By raising the front of the Van, air bubbles should collect in the top of the radiator. Loosen (not remove) the bleeder screw on top of the radiator (seen here on the left) until you see or hear air being pushed out. If you see bubbles, then there is still air escaping. Once only a solid flow of coolant is escaping, tighten the bleeder. Get behind the wheel and rev the engine to about 2000 RPM for a minute or so, then loosen the bleeder again and check for air. Repeat this process several times until no more air is being pushed out when you open the bleeder. Shut down the engine and lower it to the ground. Fill the coolant reservior to the top, and put away all your tools, except for the 13mm wrench. As the engine cools, a vacum will develop in the cooling system, which will cause coolant to be sucked out of the reservoir, and into the system. After an hour or so of cooling time, check the coolant level in the reservoir, and fill if needed.

Once done with the bleeding process, I tend to leave the grille off for a few days. Upon arriving at work or home, I will leave the engine running and crack open the bleeder valve on the radiator. It usually takes about 4 or 6 times before all the air has been purged from the system, in my experience. My new water pump is working just fine….although without the tell-tale trail behind me, I may have troubles finding my way back home! 🙂